This invention relates to a reactor for reacting gaseous or vaporized hydrocarbons with water vapor to produce carbon monoxide-and hydrogen-containing gases at temperatures above 700.degree. C and under pressure of 5-80 kg/cm.sup.2 over catalyst material contained in reaction tubes, which are indirectly heated by a heating fluid which consists of a gas that has been used to cool a nuclear reactor, particularly helium, and is at a temperature above 800.degree. C.
It is known that heat which has been produced by nuclear fission can be dissipated in a nuclear reactor by a gas, particularly helium. In such nuclear reactors the cooling helium is heated in most cases above 800.degree. C to about 1100.degree. C. The helium temperatures are preferably about 850.degree.-1100.degree. C. The helium leaving the reactor is under a pressure of about 20-60 kg/cm.sup.2.
This invention utilizes the sensible heat of the helium in a tubular heater for cracking hydrocarbons. Such tubular heater contains catalyst material in indirectly heated tubes, through which the gaseous or vaporous hydrocarbons to be reacted are passed together with water vapor. Hydrocarbon feedstocks may consist, e.g., of natural gas, which consists mainly of methane, or of mixtures of methane and higher hydrocarbons, hydrogen and carbon oxides. Hydrocarbons which have higher boiling points than methane may also be reacted if they are transformed into vapor before. A rich gas produced from vaporized hydrocarbons may also be used as a feedstock. The catalysts are in many cases high activity nickel catalysts, which contain about 5-20% by weight nickel on a heat-resisting support, such as alumina.